Diseased mitral and tricuspid valves frequently need replacement or repair. The mitral and tricuspid valve leaflets or supporting chordae may degenerate and weaken or the annulus may dilate leading to valve leak (i.e., valve insufficiency). The leaflets and chords may become calcified and thickened, rendering them stenotic and obstructing forward blood flow. Finally, each of the valves relies on insertion of the chordae inside the ventricle. If the corresponding ventricle changes shape, the valve support may become non-functional and the valve may leak.
Mitral and tricuspid valve replacement and repair are traditionally performed with a suture technique. During valve replacement, sutures are spaced around the annulus and then attached to a prosthetic valve. The valve is lowered into position and, when the sutures are tied, the valve is fastened to the annulus. The surgeon may remove all or part of the valve leaflets before inserting the prosthetic valve.
In valve repair, a diseased valve is left in situ and surgical procedures are performed to restore its function. Frequently, an annuloplasty ring is used to reduce the size of the annulus. The ring serves to reduce the diameter of the annulus and allow the leaflets to oppose each other normally. Sutures are used to attach a prosthetic ring to the annulus and to assist in plicating the annulus.
In general, the annuloplasty rings and replacement valves must be sutured to the valve annulus during a time consuming and tedious procedure. If the ring is severely malpositioned, then the stitches must be removed and the ring repositioned relative to the valve annulus. In other cases, a less than optimum annuloplasty may be tolerated by the surgeon rather than lengthening the time of the surgery to re-stitch the ring. Moreover, during heart surgery, a premium is placed on reducing the amount of time used to replace and repair valves as the heart is frequently arrested and without perfusion.